The present invention relates to compositions based on hydrogen-containing fluorochlorohydrocarbons selected from the group consisting of the dichloropentafluoropropanes, and to the use of these compositions for removing water from surfaces of a very wide variety of articles and from a very wide variety of materials.
In many machining and cleaning operations, for example in the electrical or electronics industry, the optical industry, and also, for example in the mechanical industry in the production of high-quality precision workpieces, articles come into contact with water or moisture, either intentionally or unintentionally. Water may therefore adhere (for example as a moisture film) to these articles. However, the presence of adhering water may have an adverse effect during further machining steps and/or on the serviceability and service life of the articles. It is therefore necessary for many articles to be completely freed from adhering water immediately after the machining or cleaning operations which involve the presence of water or even after mere contact with atmospheric moisture etc. before further processing or for correctly functioning use.
Such removal of water from articles is also referred to as drying. In the prior art, articles are dried by heating or by treatment with compositions ("drying compositions") comprising surface-active substances and certain solvents (such as, for example, hydrocarbons, acetone, alcohols or fully halogenated fluorochlorohydrocarbons). Since the articles to be dried can comprise a very wide variety of materials, for example plastics, glass, metals or combinations thereof, the drying processes and the drying compositions used for drying should be compatible with a wide range of materials. However, drying by heating represents an undesired, very high thermal load for the articles to be dried or is unsuitable for a wide range of materials due to the high temperatures to be used. In addition, stain-free drying is in many cases not possible in this way. In turn, the constituents in the drying compositions, in particular the solvent forming the principal component, should be inert toward a very wide range of different materials.
Although there have already been many attempts to provide drying compositions for various fields of use and for various materials, having the desired properties, such as, for example, a strong drying action, good drying quality or good inertness toward the articles to be dried, the known compositions are still, however, in need of improvement with respect to their applicational, toxicological and environmental properties. The high requirements for inertness, drying action and drying quality are not always met, or frequently only inadequately met, by the known compositions of the prior art. Alternatively, other known compositions contain relatively large amounts of solvents which are unacceptable for toxicological or safety reasons (i.e. have a low flash point). Other compositions contain solvent constituents which, due to their environmental properties, it is desirable to replace with other solvents that are at least equally suitable for the particular application. There remains therefore a need for new drying compositions which have improved properties and, in addition, are more acceptable with regard to toxicological and particularly environmental criteria.